Refrigerating apparatus



Feb. All?, 1931. F. JJKLEINHANS ET AL 1,791,964

REFRIGERATING APPARATUS Filed May 24, 1927 5 Sheets-Sheet 2 mmm/"WWW lFeb. l0, 1931. F. J. KLEINHANs ET AL 1,791,964

REFRIGERATING APPARATUS 5 Sheets-.Sheet 5 Filed May 24. 1927 Feb. l0,1931. F. .1. KLEINHANS ET AL 1,791,964

REFRIGERATING APPARATUS 5 'Sheets-Sheet 4 Filed May 24, 1927 W 00 3 4/ ZQJ 9 a W M 9M a, @y 05W/ @n 00 Feb. 10, 1931. F. J. KLEINHANS ET ALREFRIGERATING APPARATUS Fned May 24, 1927 5 Sheets-Sheet 5 awww/lionsSz/Lam. ula JV Patented Feb. 1U, i931 UNITED s-rATEs PATENT OFFICEFRANCI'S JOSEPH KLENHANS AND HERMAN A. BRANDT, OF BUFFALO, YORK,ASSIGNORS TO ARCO VACUUM CORPORATION,'OF YORK, N. Y., A CORPORATION OFDELAWARE Application led May 24,

Our invention relates to new and useful REFRIGERATING APPARATUS 1927.serial N6. 193,830.

1, with the closure panels for a lower comimprovements in refrigeratingapparatus, Dartment in place;

and while it embodies features which render it useful and applicable forrefrigeration gen- 5 erally, it will be found especially applicable anduseful in a structure o r system for domestic refrigeration, that is,for installation in a refrigerator box or cabinet for domestic use inthe refrigeration and preservation of foods. The invention relatesparticularly to that type of refrigeration in which rapid evaporation ofwater or an aqueous liquid body is employed as the agency for veectingthe production of temperatures low enough to produce a refrigeratingeffect, and in which the rapid evaporation to produce low temperaturesis effected by creating a sulfi- Vciently low sub-atmospheric pressureover the body of water or aqueous liquid and withdrawing the watervapors at such rate thatl the temperature of the liquid body is reducedto a point satisfactory for the desired or determined cooling orrefrigerating effect.

An object of this invention is to produce an improved refrigeratingapparatus which will operate efficiently to produce the desired lowtemperature by the eiiicient use of low sub-atmospheric pressures over abody of water, or, if desired; over a mixture of water and a lowerfreezing point medium, and thus rendering the apparatus available forcihcient and practical use in a system operating on the evaporationprinciple above stated.

The invention consists in the improvements to be more fullydescribedhereinafter, and the novelty of which will be particularly pointed outand distinctly claimed.

We have fully and clearly illustrated a preferred embodiment of ourinvention in the accompanying drawings to be taken as a part of thisspecification and wherein- Figure 1 is a view in front elevationof ourinvention as embodied in a refrigerator box or cabinet for domesticrefrigeration, the door of the cooling chamber jor food compartment andthe space for the cooling element being shown open and in edgeelevation; y

Fig. 2 is a section on the line 2`2 of Fig.

Fig. 3, is an enlarged sectional view through the cooling element andfreezing chamber, taken on the line 3--3 of Fig. 1, with the door of thefood chamber closed;

Fig. 4 is a sectional view on the line 4 4 of Fig. 3 with the centralfreezing pan removed; Fig. 5 is a top plan view of the exhausting meansand drivlng motor, and means for separatin water and lubricantdischarged from the ex austing means, parts being broken away, andpartly in section;

Fig. 6 is a rear elevation of the water and lubricant separating meansshown in Fig.

5parts being broken away, andpartly inI section Fig. z7 is a view'in endelevation, with parts roken away and partly in section of the housingfor the exhausting means, and showinglin section a separator for air andvapors, and also showing an automatic control means for lubricant;

Fig. 8 is a vertical central section through one form of automaticvvalve forming one of the elementsl of our5w invention, having its capmember"removed to show the lead terminals;

. Fi 9 is a section on the line 9--9 of Fig. l

10 o one form of pump which may be employed as the exhausting means forthe embodiment of our invention herein shown and described;

Fig. 10 isa section on the line 10-10 of Fig. 9;

Fig. 11 is a diagram of a circuit system for supplying and controllingelectric current to the several electrically driven and controlledelements, the same being shown in the condition when the system is beingoperated to perform refrigerating functions;

Fig. 12 is a View ofthe circuit system shown in Fig. 11, but in thecondition when the system is at rest, that is, not operating tocreaterefrigerating conditions or functions;

Fig. 13 is a det-ail of part of the circuit system showing the controlswitch when moved to another position controlling operation of themachine, and

full lines the switch blades at an intermediate of? position whenrotated from position shown in Fig. 11 to position of Fig. 13, andshowing in dotted lines the blades at a second intermediate off positionwhen rotated from position of Fig. 13 to position of Fig. 11.

Referring to the drawings by characters of reference,1 designatesgenerally a refrigerator box or cabinet of any design and constructionsuitable for domestic refrigeration. lln the embodiment shown, this boxor cabinet may comprise a front wall 2, rear Wall 3, side walls 4, 5, atop wall 6, and a bottom or floor 6a. The walls mentioned preferablyconsist lof outer sheathing or panels 7 and inner walls 8 s acedtherefrom to receive suitable intermediate heat insulating packing 9(see Fig. 2) of any suitable material serving to insulate the interiorofthe cabinet from the higher external temperature, and maintain thedesired low temperature conditions created in the cabinet. The cabinetis divided at a point intermediate its upper and lower portions by meansof a horizontal floor or partition 10, into a lower compartment 11 andan upper compartment 12. The compartment 11 constitutes a space orchamber to receive certain apparatus, to be hereinafter described,forming part of our refrigeration system, and the upper compartment 12forms a space to serve as a food compartment, above which is a space 12to receive a cooling element by which the desired cooling effect isproduced for cooling the food compartment. The front wall 2 is providedwith a suitable door opening 13, through which access may be had to thechamber 12, said opening being controlled by a closure door 14 hinged tothe front wall, as at 15, and being of any construction suitable for theurpose for which it is employed. The food) chamber 12 may containsuitable shelf grids 121? to support food or other substances to bepreserved or cooled.

The floor 10 is also formed of inner and outer sheathings 7a withintermediate heat insulating material 9 in the same manner as describedwith reference to the outer walls of the cabinet. t

The bottom, side, rear and top walls of the upper chamber 12 andtheinside of door 14 may be lined witha suitable sheet-metal, as at 16.

The lower compartment 11 is preferably provided at the front and rear ofthe cabinet with openings 11E, normally closed by removable perforatepanels 11b which conceal the elements in said com artment, but which maybe readily detac ed for access to the com artment and said elements.

'l e upper compartment 12 contains a horizontal baiiie or partition 17which divides the 'interior of the chamber 12 to form the foodcompartment at the lower portion thereof, and to form the refrigerationspace 12a at the merece upper portion thereof, in which the coolingelement to be hereinafter described is located.

From the front edge portion of the partition 17 rises a vertical frontwall 18 which extends upward to the top wall 6, and also 7 extendsentirely across the front of the compartment to thereby form the frontwall of the space 12a. The side edges of the wall 18 are provided withforwardly projecting side plates or flanges 19 which are adapted to besecured by suitable fastening devices 2O to the vertical sides of theopening 13, to there by support said partition 17 and Wall 13.

The side edges of the partition 17 do not extend horizontally entirelyacross the space 12, but terminate short thereof', as shown at 21 inFig. 4, and from these side edges rise vertical side walls 22 which arespaced from the adjacent side walls of the compartment to form verticalair ducts 23. The upper horizontal edges 24 of the walls 22 terminate,a-s at 25, at a distance short of the upper wall of the compartment 12ato provide passages 26, through which air flowing upward through theducts 23 may pass into the space bounded by partition 17, walls 18, 22,and the top of the compartment 12a. The Vspace formed in the manner justdescribed is provided to receive the cooling element of the system.

rlhe partition 17 isprovided with an opening 27 above which is supporteda suitable air delector plate 28, the arrangement beingl such that thewarmer air which passes from the food compartment 12 up through ducts 23and passa es 26, will be cooled in the space containing t e coolingelement, and then return through opening 27 into compartment,

12 to maintain the same at the desired low temperature. The side edgesof the deflector plate 28 overlie or extend laterally beyond the edgesof the opening 27, for a purpose to be presentl described.

The various walls 17, 18, 19 and 22 are preferably of sheet-metal andmay be made integral either by stamping from a single sheet, or may bemade separately and welded together to form the structure described.

Within the cooling space above described is located a cooling element29, in which the desired lower temperature is produced so as to extractthe heat from the air currents flowing in contact with `the wallsthereof. This element in its preferred embodiment consists of arectangular metal container which is liquid and air tight, except ashereinafter setr forth, and includes a vertical front wall 29, rear wall30, bottom wall 31, top wall and side walls 33, all preferably ofsheetmetal and formed or united to provide a substantially rectangularhollow or chambered element. This element 29 is of such vertical. andtransverse dimensions and is so supported that the side walls are spacedfrom the walls A22 to form vertical side air duct-s 34 comtraineemunicating with passages 26, and the bottom wall 31 is spaced above thel.Epartition 17. By this arrangement the air rom chamber 12 passes upthe ducts 23, through passages 26, down through ducts 34 and underthecooling element to the opening 27, and is cooled by contact with sideand bottom walls of the element. rlhe cooling element is of such frontto rear dimension that the front and rear walls thereof are spaced fromthe wall 18 and the rear wall of compartment 12a to form additional airHow ducts 35, 36, and the top wall is spaced from the top wall of thecompartment to form an air flow space 37. By the arrangement of thecooling element in the manner described, the warmer air rising from. thefood compartment is caused to circulate efliciently in contact with thecooling element, be reduced in temperature, and returned by gravity tothe food compartment to maintain the desired low temperature therein.rll`he deflector plate 28 is so located beneath the cooling element thatany dew formed thereon will be deflected on to the plate 17 andprevented from dropping through the opening 27' into the foodcompartment. Moisture lcollected on plate 17 may be drained 0E through apipe 17a to any suitable receptacle (not shown).

'lhe cooling element described is adapted to contain an aqueous bodywhich may be water entirely, or a mixture of water with some other fluidhaving a lower freezing point than water, for example, glycerine, whichfreezes at approximately minus 40 F.,vso as to reduce the freezino`point of said body below that of water. advantageous because of its lowfreezing point, but also becauseof its high boiling point ofapproximately 338 F., which insures against evaporation of the glycerinealong with the water. The overall dimensions of this cooling element mayvary within the scope of our invention, but in one embodiment builtaccording to the disclosure herein, the dimensions are 14" wide by 14"long by 9 high, providing a cooling'surface of 6.2 square feet exposedto the air" currents circulating as above described in the box. j

The cooling element may be supported in the relation described by anysuitable means, for example, by underlyingtransverse supporting bars 38,supported by the lower ends of hanger rods 39, the upper ends of whichare headed and held by slotted clips or brackets 40 bolted, as at 41, tothertop wall of the cabinet. lBy this means the element may be readilyapplied in and detached from operative position.

Within the liquid containing space of the cooling element is located afreezing compartment 42, which is preferably in the form of ahorizontally disposed fluid-tight shell comp'osed of a bottom wall 43,'side walls 44, top wall and rear wall 46. The front portion lycerine isparticularly*- of the shell is leftiopen to provide a door i opening tothe interior thereof, and projects through registering openings 47, 48,respectively, in the walls 29a and 18, so that access may be had to thefreezing compartment from the front of the refrigerator cabinet. rlhedoor opening is adapted to be closed by a drop door 49 hinged, as at 50,to keepers 49a fixed on wall 29a and extending through slots in wall 18,as at 50a, the door having a packing facing 51 of rubber or equivalentmaterial adapted to make an airtight seal with the front projecting edgeof the freezing compartment, as will be presently described.

rlhe freezing compartment is supported in the cooling element bysuitable vertical spacer bars 52, in such manner that the compartment isspaced from the walls of the element and is surrounded on all sides,except at the front, by the liquid refrigerating medium in the coolingelement.

The freezing compartment is divided by apertured partitions 52a intopigeon holes 52h, and is adapted to receive suitable removablereceptacles, such as trays 53, adapted to con- (tain water or othermaterial to be frozen or cooled, said partitions being shown in full anddotted lines in Fig. 3 and in section in Fig. 4.

`We will now proceed to describe the means for producing the desiredcooperative effect in the cooling element, and in the freezingcompartment to produce refrigeration and cooling or freezing. rearportion of the cooling element above the liquid level therein is anexhaust or suction conduit 54, which communicates with the interiorofthe element. The conduit adjacent its point of connection with thecooling element passes through the rear wall of the cabinet and ythencedownward on the exterior thereof, and is then directed into the chamber11 where it communicates through a union 55 with the inlet port 55a of asuitable exhausting or evacuating means 56 capable of producing therequired sub-atmospheric pressure in the cooling element to result inthe necessary rapid evaporation of the water to lower the temperaturethereof to the degree desired. The evacuator should have sufficientvolumetric capacity to remove thevapors with sufficient rapidity tofacilitate rapid evaporation with consequent eliicient lowering of thewater temperature. In Figs. 9 and 10 of the drawings, we haveillustra-ted one form of pump or evacuator capable of achieving theresults sought, said pump not'v being of our invention either jointly orseverally, the same being merely by way of example. The exhaust from theexhausting means is discharged through an exhaust port 57.

The pump or exhauster shown comprises in general a casing'` 58containing a cylindri- Connected to the upper v.

shown herein cal chamber 59 from which projects a hollow boss 60, towhich the inlet *L opens. In thel chamber is a cylindrical member 61eccentrically mounted on a shaft 62, mounted in suitable bearings in theend walls of the casing, and one end of which projects external of 1thecasing, as at 63. Rotatable on the cylindrical part 61 is a. cylindricalpiston sleeve 64, the circumference of which at one point closelyapproaches and rolls on the wall of the chamber 59, a`s at 65, to make aseal contact. The sleeve 64 carries a rigid, radial abutment 66 whichslides in a rocking bearing member 67 between the chamber 59 and thechamber of boss 60, and projects into the latter chamber. The abutment66 is hollow as at 66;` and at its base is provided with ports 68,whereby the vapors exhausted from the cooling element entering boss flowthrough abutment passages 66a and ports 68 into the inlet side a of thepump chamber. Then as the piston rotates in the direction of the arrowthe v apbr drawn into the pump is forced on the next revolution to theexhaust side and is discharged through the exhaust 57. ln the dischargeduct 57 is arranged an inwardly closing check valve 57, of any suitableconstruction, which opens to permit expulsion from the exhaust side ofthe piston, but which is urged to closed position by a bow-spring 575 toprevent any liquid in the housing being drawn into the pump chamber.Fixed on the projecting end 63 of the piston shaft, is a belt pulley-69,which is driven by a power belt 70, in turn driven by a pulley 71 on theshaft 72 of a. suitable prime mover, preferably in the form of anelectric motor 7 3, mounted on the same base as the pump. The pulley 69may be equipped with fan blades 69a to cool the Working elements.

In operating this system, we `have found that a pump of the characterillustrated having a chamber, the internal dimensions of which are 7 by7, and in` which the rotor or piston is of such diameter that thegreatest radial distance between its circumference and the wall of thechamber is 21/2, and,

therefore, having a displacement or volumetric capacity of 158 cubicinches per revolution, will, act to produce satisfactory cooling andfreezing when driven at the rate of 305 revolutions per minute. When apump of the capacity stated is. driven at this speed, it will producetemperatures corresponding to the freezing point of water, and in sodoing will produce a low sub-atmospheric pressure of about .1806 inchesmercury absolute, and will also produce temperatures below the freezingpoint of water with correspondingly lower sub-atmospheric pressures. 1twill be understood, however, by those skilled in the art, that the areaof the surface of the liquid in the cooling element may be properly Yproportioned relative to the pump capacity to produce the .desired rate.of evaporation, and, consequently, the desired refrigeration effect. i

lt will also be understood that the volumetric capacity of the pump inoperation is directly related to the temperature of the vapor evolvedand to the refrigerating effeet desired. lt is known that at 32 F. apound of water vapor occupies 3296 cu. ft. and the evaporation of apound of water is equivalent to 1073 B. t. u.s, while at 20O ll'. onepound of water vapor occupies 5650 cu. ft. and theevaporation of a poundof water at this temperature is equivalent to 1223 B. t. u.s, from whichit will be seen that if a refrigerating effect of 500 B. t. u.s per houris desired, so as not to produce a temperature below 32 F., a pumpcapable of displacing 28 cu. ft. per minute or 1600 cu. ft. per hour,would be sufficient For lower degrees of temperature, pumps of greatercapacity would be required. From this it will be apparent that thegreater the volumetric capacity of the pump the greater will be therefrigerating effect produced per hour at the same lt. P. M. rlhe motoris supplied with electric current from any suitable source, but weprefer to employ a control circuit-to be described hereinafter.

The freezing conditions in the freezing l compartment are preferablyachieved by connecting the interior thereof by an exhaust connection 74with the pipe 54, so that in the embodiment shown, the exhausting meansor pump will simultaneously create a low sub-atmospheric pressure in thefreezing compartment as Well as in the cooling element. By thisarrangement thefood compartment is cooled, and at the same time watermay be frozen in the trays in the freezing compartment. This provisionalso enhances the freezing action because of the external cooling effectof the cold liquid in the cooling element and the direct effect of thelow sub-atmospheric pressure in the freezing chamber. lt will be notedthat the low pressure or approximate vacuum in the freezing chamber willserve to maintain the door 4:9l in air-tight, sealed engagement with thefront edge of the freezing' chamber so long as such low pressure exists.

The pump constituting the exhausting means is arranged in a suitablehousing 74, which serves as a receiver for the discharge from the pumpand a container for a body of water and oil which submerges the pump toa point above the discharge 57, and seals the pump against any ingressof air thereto which ,might interfere with its vacuum producingcapabilities. The housing-74 is provided with a suitable inletconnection and hand valve 7 4 by which the housing may be supplied withan initial quantity of oil and water, preferably equal parts, necessaryfor operation ofthe device. The water and oil may also be replenishedthrough the said connection and valve. The housing is also supplied witha drain c ck 7 4l (Fig. 7) by which the contents of the ousing may bedrained, if desired. In this arrangement the discharge from the pumptakes place directly into the interior of the housing, and inasmuch asthe matter discharged may comprise air, water, water vapor andlubricating oil, we provide means for separating oil and water from theair and discharging the latter from the housing. This means comprises aclosure wall for the top of the casing, which includes an inwardlycupped plate 7 5 having distributingperforations 76, and over which isplaced a layer of suitable fibrous packing material 77 coveroutletopening 81.

ing the perforations 76, through the interstices of which fibrousmaterial air alone may pass. Over the sheet 77 of fibrous material, isarranged a metal plate 78, said plate and the sheet of fibrous materialbeing of such dimensional area as to leave a marginal air passage space79 about the periphery thereof. Overlying the plate 78 and spacedtherefrom, and of such area as to cover the marginal space 79, is a topplate 80 having a central air The exhaust from the pump passes throughthe liquid in the housing and strikesr the underside of plate 75, anyoil and water carried by the air being thrown back into the housing, andthe. air passing through perforations 76, fibrous material 77, space 79and the space between plates 78 and 80 emerging through outlet 8l. Bythis arrangement only airis thrown out of the housing. Any water vaporpresent condenses and together with oil straties in the housing, asindicated by the level llines marked Oil and Water in Fig. 7 of thedrawings. Incidently, this arrangement may to some extent act as amufier of any noise arising from operation of the pump.

l/Ve will now describe means, also of our invention, for separating thewater from the body of oil in thehousing and returning it to the coolingelement so that the supply of water therein necessary to produce thecooling effect will not become prematurely depleted to such an extent asto require too frequent replenishment from an outside source.

82 designates an oil and water separator, 'preferably in the form of atank having. a primary receiving chamber 83. The receiving chamber` hascommunicating therewith at its upper portion, as at 84, one. end of apipe A85, the other end of which enters the housing 7 4, and is directeddownwardly therein so that the open end of said pipe will be located inthe Vbody of water in the housing, preferably close to but just .abovethe bottom of the housing. y It will be apparent that due to the weightof the liquid body in the'housing,

water with some. oil from the bottom of the housing-Wi1l iow throughpipe 85 into the primary receiving chamber 83. The separator 82 inaddition to the chamber 83, has a plurality of separating chambers,indicated at 86, 87, formed by vertical partitions 86, 87, segregatingthe chambers, and these chambers are connected in sequence by Howpipes88, 89, the pipe 88 having an inlet end adjacent the bottom of chamber83, and a discharge end delivering through partition 86a into the topportion of chamber 86, while the pipe 89 is arranged similarly inchamber 86 and delivers through partition 87 a into the top portion ofchamber 87. It will be seen that by this arrangement water, togetherwith some oil, will flow from the housing 74 through pipe 85 into theprimary separating chamber 83,- wherein the water and oil will separatein part and stratify in said chamber, the,

water being at the bottom of the chamber. The water so separated outwill flow successively through pipes 88 and 89 to the chambers 86, 87where further separation takes place until the final chamber 87 containswater free or substantially free of oil. It will be understood that theseparator may contain as many separating chambers as may be required toproduce satisfactory separation. We have shown this separator as locatedon the base and external to the housing, but it may be located withinthe housing, if desired, without changing its construction or principleof operation( Each of the pipes 88, 89 may be provided at the inlet endsthereof vwith any suitable form of straining or ilteringdevice 88EL topass water but eliminate oil and dirt particles from the water to bereturned to the cooling element. A

Eachof the chambers 83, 86 and 87 may be provided with a drain cock 83a,by which the contents of said chambers may/be withdrawn when desired.Leading from the chamber 87 tothe cooling element, is a water returnpipe 89, which may also have a ltering device 88a, and through whichlwater may be returned from said chamber to the cooling element byyvirtue of the vacuum or low sub-atmospheric pressure existing in thelatter. This conduit 89 may include a flexible connection 89b having aslip or telescoping connection 89c with a metallic section, so as to bedetachable therefrom for a purpose to be presently set forth. Returnflow through the return pipe is controlled by an automatic valve 90,which is constructed and controlled-so as to-be closed while theexhausting means is operating to create sub-atmospheric pressure, in thecool ing element, and to be opened tb lpermit water to return to thecooling .element when the exhausting means comesuto rest. Bythisarrangement the water return pipe is closed to permit creationofl thedesired low pressure in the cooling element during operation ofthe maybe a magnet or solenoid operated valve, as shown in Fig. 8. The. valveillustrated includes a body 91 having inlet and outlet passages 92, 93,connected in the pipe 89a and separated by a partition 94 having a port95 and seat 96. Cooperating with the seat 96 to open and close the port95, is a valve head 97 carried on the lower end'of a vertically movablevalve stem or plunger 98.

Mounted on the valve body 91 is a casing 99 enclosing a hollow magnet orsolenoid winding 100, in the hollow portion of which is arranged asleeve 101 in which is housed the upper end of the valve stem 98. Theupper end of the tube 101 is closed by a head 102 between which and thetop of the stem is arranged a spring 103 which normally exerts its forceto move the valve stem and the valve head 98 so that the latter will heseated on the seat 96 to close the port 95. The arrangement is such thatwhen the magnet or solenoid is energized, it will raise the valve stemor plunger to lift the valve from its seat and permit How through theport 95, but when the magnet is deenergized the spring 103 will move thevalve to closed position. The magnet or solenoid winding is arranged ina circuit system to`be hereinafter described, which in the embodimentshown may be so controlled that the magnet will be deenergized forclosing the valve whenever current is suppliedto the motor 73 to drivethe exhaustin means, but will be energized to move the valve to openposition when current to the motor 7 3 is discontinued. 'Lead terminalsfor the winding are shown at 100B.

We-will now proceed to describe means for supplying lubricating oil tothe pump or eX- hausting means 56, and for maintaining the supply oflubricant thereto forproperlubrication andv sealing thereof. Asheretofore stated, the housin 74 contains a body of liquid, consisting oa lower stratum of water and an upper stratum of oil. Leading from thehousing at a point high enough so as to always be in position to receiveoil from the oil stratum, is the inlet end of an oil feed pipe 104,which is led through the wall of the housing to a point externalthereof, and is then returned within the housing and connected to one ofthe bearings for the pump Yshaft 62, which bearing communicateswiththeinterior of the pump chamber. The arrangement is such that whenflow is permitted through t-he pipe 104, the suction or lowsub-atmospheric pressure in the pump chamber will operate to drawlubricant from the stratum of oil in the housing and deliver such oilthrough the shaft 105 adapted to` establish iiow of lubricant throughthe pipe 104 while the pump is in op` eration and requires lubricationand sealing, and to cut off supply of lubricant when the pump is atrest. This valve 105 is preferably electrically and automaticallyoperated so as to open when ever current .is supplied to the motor todrive the pump, and to close to cut off supply of lubricant when currentto the motor is discontinued. rllhe valve may take a number of formsavailable for the purpose, without departing from the spirit and scopeof our invention, and may be of the form illustrated in Fig. 8 andheretofore described. In the pipe 104 may be arranged a manuallycontrolled valve 104 which may be of any suitable type permitting manualadjustment to regulate the rate of flow of lubricant passed from thehousing and through the automatic valve to the pump bearing and pistonor rotor chamber.

We will now describe an electric circuit system for controlling supplyof current to the motor 73 and the valves 90 and 105, in order toaccomplish the refrigerating action and the operation of said valves, asheretofore described, reference being particularly had to Figs. 11 and12 of the drawing. Located at any suitable point in the system wherebest subject to variations in temperature which may be employed as theagent to control the system, is a thermostat 106, the same beingpreferably located .in the food compartment 12, and for the purposes ofthis application being shown as of the type including a double polemercury switch 107. embodying a tube or vessel, which is adapted to betilted by thermostatically responsive means, not shown, to shift themercury to establish the circuit at one pair of poles, and break thecircuit at the other pair of poles. rThe switch 107 contains at each ofits opposite ends a pair of contacts 108, 109, respectively, and alsocontains a body of mercury 110 adapted to immerse either pair ofcontacts to establish current therethrough according to the direction inwhich the switchY tube is tilted. Such switches are readily available onthe market, and, therefore, a specific description of the structurethereof need not be set forth herein, except in so far as may benecessary for a disclosure and understanding of the manner ofcontrolling the circuit system.

The source of current may be from any suitable point, for example, acommercial line circuit,`and is indicated by the leads 111 112, whichconnect to protective fuses 113. The lead 111 is connected to theinnermost of the pair of contacts 108, and the lead 112 connects to oneof the contactsof a threepole cord connector or socket 114, which'may beof any of the well known commercial types. The other or outer contact108 is connected by a lead 115 with a contact L of a :merece rotary handswitch, of a type known en the market as a Perkins doublepnle,doublethrow snap switch,-tlie same being indicated at 116. The innermostof the other pair of switch contacts 109 is connected by a lead 117 tothe lead 111. The outermost contact 109 is connected by a lead 118 withthe other point L2 on the switch 116.' Tntermediate the switch pointsL', L2, are contacts 119, 119a and 120, 1202, and the switch includes apair of rotary contacts or blades 1152, 1182, shown diagrammatically inFigs. 11 to 14, by which the circuit may be completed from the pointsL", L2 to said contacts and bridge across from contact 119 to 1202, orfrom 119a to 120, added jumper leads 1191), 119C, as indicated,connecting these contacts. Contact 120 is connected by a lead 121 to asecond of the contacts of the connector 114, and contact 1202 isconnected to the third contact ot connector 114 by a lead 122. Thecontact to which lead 121 is connected in the connector 114 is connectedby a lead 123 to the motor circuit or windings 124 of the motor 73, thereturn lead oit' the motor being shown at 125 and connecting to theconnector 114 at the point to make circuit with the line lead 112. Thewinding or core 100 for the control valve 105 heretofore described, isbridged across the leads 123 and 125 through suitable connections 126and a two-pole plug connection 1262, if desired. To the third contact ofthe connector 114 is electrically connected a circuit lead 127, which isin circuit through the lead 122 with the contact 1202. This lead 127connects to one end ot the wire for the coil 100, which operates thewater valve 90, the other end of said coil winding being connected tothe lead 125. The coil for the water valve may be connected into thelead 127 by a two pole plug 1272. It will be seen that with the parts inthe position shown in Fig. 11, with the contacts 108 in the switch tubeimmersed in the mercury and the hand switch 116 operated to cause theblade 115* thereof to connect the switch points L, 119a and 120. themotor circuit will be energized to drive the exhauster pumpL' andsimultaneouslv' therewith the winding 100 f the magnet for operating theoil control valve 105 will be energized to cause the valve to open topermit 'low of oil from the pump housing 74 to the pump bearing and thepiston chamber of the pump. The conditions just described are thosewhich exist when the thermostat has been a'ected bv higher temperaturesto throw the mercury switch to immerse the contacts 108 in the mercury.This condition continues so longas the temperature is high enough tocause the thermostat to tilt the mercurv, switch to the positiondescribed.

When the temperature produced and controlling the thermostat falls lowenough to actuate the thermostat to throw the mercury switch to theposition shownin Fig. 12,5the

from the lead 111 the current Hows to the innermost of the tube contacts109, through the mercury to the outermost Contact and throjugl the lead118 to the contact L2 at the rightifo' lthe double pole switch 116,thence through blade 118a to the contact 1202, and by way of the lead'122 and lead 127 through the winding 100 of the water valve to lead125. By way of lead 125 the current passes through the connector 114 tothe line lead 112. 1n this condition of the circuit it will be seen thatthe water valve is opened to permit flow of water from the separator tothe cooling element whenever the motor and pump are at rest, and therebyadds an increment of water to the body in the cooling element tomaintain the desired quantity therein. It will lbe seen that when thecircuit is in the condition shown in Fig. 11, current to the lead 127and the coil `for the water valve. will be cut off so that the valveplunger will be released from the magnet and the spring 103 will seatthe valve and thereby prevent flow of water from the separator to thecooling element.

While the circuit is in the condition shown in Fig. 11, if for anyreason it should be desired to stop the motor and pump, the double poleswitch 116 may be moved to the position shown in Fig. 13 to make Contactat L, blade 1182, 119, jumper. lead 119c andcontact 120,

thereby cutting ofi' the current to the motor and establishing thecurrent to the coil for operating the water valve. This arrangementprovides for a manual control independently of the thermostaticautomatic control. The flow of. current when the parts are in thiscondition is from lead 111 through the contacts 108, lead 115, switchpoint L', contact- 119, contact 120% to lead122, and thence A throughthe water valve magnet, as heretofore described. It for any reason itshould be desired t0 start operation of the pump when the same is atrest, and independently of the thermostatic control, and when themercury switch is in the position shown in Fig. 12, the switch 116 isoperated to cause blade 115EL to bridge the contacts4 L2, 120, underwhich conditions the current flow is as follows: from lead lllthroughthe lead 117 to the innermost contact 109, thence to the 'outermostcontact 109 and lead 118 to the switch contact L2, thence to contact120, and` by leads 121, 123 to the motor and oilvalve coil. Under theseconditions the water valve magnet is cut out of the circuit system andthe water valve closed.

rlhe parts being constructed and arranged as above set forth, theoperation of a preferred embodiment of our invention is as follows: Thecooling element 29 is supplied with either a body of water, or a mixturecompris ing a liquid body of glycerine and Water, preferably in theproportions by Weight of about seventy per cent-of water to thirty (30)per cent. of glycerine, the total quantity of liquid being such that thelevel thereof will be below the inlet to the suction duct 54, so that anair or vapor space will be left above the liquid, and the latter willnot be drawn as liquid through the suction duct. ln a. system of givencapacity the liquid may amount to three and one half (3l/2) gallons, andthe proportions of the element 29 being such that with the liquidquantity mentioned there will be about 1.36 square feet of evaporativesurface. The trays or other receptacles in the freezing chamber may besupplied with zvater or other ingredients to be frozen or cooled. Thecooling velement 29 may be charged with the water or aqueous mixture bydisconnecting the flexible pipe connection 891 from the section 89a andconnecting said connection to a vessel (not shown) containing thedesired quantity of water or aqueous mixture, and then operating thehand switch 116 to cause the exhauster to create a low enoughsub-atmospheric pressure in the cooling element 29 to draw the chargefrom the vessel into the element 29. `When charging, the amount of wateror aqueous mixture placed in the vessel may substantially approximatethat desired to form the charge in the cooling element. The housing 7 4will also be supplied with a quantity of water and suitable lubricatingoil, as indicated in llig. 7 of the drawings. For initial starting, themotor and pump will be at rest, the oil valve closed and the water valveopen, the circuit being in the condition shown in Fig. 11, due 'to-thefact that the food compartment is relatively warm and the thermostat hasassumed a position to hold the mercury switch in the position shown inFig. 11. The switch 116 is then operated to throw the current on to thesystem, whereby the motor 73 is'energized and the oil valve magnet alsoenergized to open the oil supply connection 104. At the same time thecircuit to the magnet of the water valve is interrupted and the watervalve moves to closed position. The motor when energized drives thepump, and the latter operates to evacuate' or exhaust the space abovethe liquid level in the cooling element, resulting' in rapidevaporationof the liquid 'which causes the temperature of the liquidtowbe lowered ata. rate, depending upon the degree .of sub-atmosphericpressure created "avancee in Said space. "When the liquid evaporates,the vapors liberated therefrom are carried out by the pump suction, andpassing through the duct 54 enter the pump and are discharged therefromthrough the discharge 57. In View of the great affinity of glyc-crinefor water., these two elements are intimately mixed in the coolingelement, but in View of the difference in boiling points, the wateralone will evaporate and be carried over as vapor through the suctionline. The glycerine remains in the cooling element. YVth a pump ofsuficient volumetric capacity to cause a substantial vacuum over thesurface of the liquid in the cooling element, the evaporation will takeplace so rapidly that the temperature of the liquid, andconsequentlythat of the cooling element, will be rapidly reduced towardthe freezing point of the water, or lower, depending upon the degree ofvacuum produced. By employing a mixture of water which freezes atapproximately 32 F., yand glycerine, whiclrfreezes at a lowertemperature, approximately 40 F., the temperature of the liquid in thecooling element may be carried to a point below that of the freezingpoint of water, so that low temperatures may be produced, if desired,and suiciently low to create elicient freezing conditions around thefreezing chamber Without freezing the mixture in the cooling element.Simultaneous with the suction created in the cooling element, the vacuumor low sub-atmospheric pressure is also produced in the freezingchamber, so that water or other substance therein will be frozen, cooledor congealed, according to the degree of vacuum produced and thecharacteristics of the material placed in the freezing chamber.

During this operation of the exhausting means or pump, the oil valve 105will be open and the suction created in the pump chamber will draw insmall quantities of oil, but sufficient to properly lubricate thebearings and form a 'seal between the surface of the pump piston orrotor sleeve and the'cylinder wall. The air and' water vapor withdrawnby the pump from the cooling element and the freezing chamber, areexpelled from thedischarge VY57 of the pump into and through the-bodyofliquid in the housing, and together'therewith will pass small quantitiesof oil, some of the water vapor not condensed during compression by thepump being condensed by contact with the liquid in the housing. Theairwcarrying any water vapor not condensed, or oil particles notseparated out, will pass upward from the liquid bodyand against theoil'and airseparator made up-of the elements 75 7,7V and 78, the watervapor and oilbein'g Septirated out and fallingback into the housing,while .the air is expelled frointhe port', 81. The oilandwater separatedout 'remain'n the housing and a portion of 'thejwater'with someta muy@,frpugthahtniagthrough pipe 85 to the primary chamber 83 of the oil andwater separator, wherein the oil and water will stratify and beseparated as described, substantially oil-free water finally reachingthe chamber 87. This flow of water willtake place whenever there is agreater level of liquid in the housing thanin the oil separator, and isassisted in part by any pressure which may exist over the surface of theliquid in the housing. This operationcontinues so long as thelthermostat acts to maintain the switch 107 in the position shown in F11.

When the system has operated long enough to create the desired ordetermined low tem-Y perature condition in the food compartment,

or other point of control, the thermostat operates to move the switch107 to the position shown in Fig. 12, under which conditions the circuitto the motor will be discontinued and the pump brought to rest.Simultaneously with stopping of the pump, the current to the oil'valvecoil will be discontinued and further flow of oil from the housing 74 tothe pump and its bearings will be stopped, even though a sub-atmosphericpressure exists within the pump when brought to rest, although thesuction may drawA in the small amount of lubricant between the valve 105and the pump. The system being air andiuid-tight, the pump piston-beingoil-sealed, and the discharge therefrom being provided with an inwardlyclosing check Valve, the low sub-atmospheric pressures created will bemaintained for a considerable time after the pump has come to rest. Itwill thus be seen that the oil flow to the pump will be establishedwhenever the pump is operating to draw a sub-atmospheric pressure, andwill cease whenever the pump is stopped. Simultaneously with thestopping of the pump and theclosing of the oil valve, the current willbe thrown upon the coil for the water valve 90, and the latter will beimmediately opened, so that the suction existing by reason of the lowsub-atmospheric pressure in the cooling element will serve to draw backa certain quantity of water from tank 87 into the cooling element tomake up for any water losswhich may have resulted, due to evaporation,while the pump was running. By this provisionwater loss is minimized andreplenishment of water in the cooling element from a source outside thesystem will not be required as often as wouldbe the case if thisautomatic water return were not provided. The parts remain in thiscondition until the temperature rises to a point suliicient to actuatethe thermostat to again shift the tube 107 to the position shown in Fig.11, whereupon the operation above-described is repeated until thetemperature drops low enough to cause the thermostat to throw theswitch, 107 back to the position shown in Fig.r12.

Inorder to relieve, any excessive starting load onsthe pump land motor,which might .exist when the pump is started from a posi- -cause theresistance of such air to be reduced by relieving the pressure throughthe by-pass into the inlet side of the pump when the latter starts. Itwill be understood that during normal operation of the pump, the reliefvalve is seated and held shut, and that it opens to relieve the pressureonly at starting.

It willbe noted that the'pump when running operates to evacuate theinterior of the cooling element and simultaneously therewith theinterior of the. freezing chamber. By this operation not only is thefreezing chamber evacuated at a rate to produce rapid freezingconditions therein, but the liquid in the cooling element is cooled downto a point which will rapidly lower the temperature of the wall of thefreezing chamber and thereby facilitate freezing in the freezingchamber. This is true whether the liquid in the cooling element be wateror an aqueous mixture, such, for example, as water and glycerine, asdescribed. It will beunderstood that by employing a mixture of water andglycerine (which freezes at a temperature much lower than water), themixture will have a lower freezing point than that of water, andtherefore higher vacuums may be employed with resulting lowertemperatures than is possible with the use of water alone. This permitslow temperature (below the freezing point of water, if desired) of theliquid in the cooling element, and also facilitates freezing It will beunderstood that while the pumpy is running and creating the lowsub-atmospheric pressure in the freezing chamber, the door or closure 49will be held closed to seal the opening to the freezing chamber, due tothe preponderance o'f external atmospheric pressure, However, when it isdesired to obtain access to the freezing chamber, it is only necessaryto operate the switch 116 to bring the system to rest,-whereupon thepressures within and external to the freezing chamber will becomebalanced suiciently to permit the door to be readily opened.

What we claim and desire to secure by Letters Patent of the UnitedStates is:

1. In an apparatus of the character described, a cooling chamber adaptedto cont-ain an aqueous liquid, a freezing chamber within `said coolingchamber, and evacuating means to produce simultaneously a lowsub-atmospheric pressure in said chambers.

2. In an apparatus of the character described, a cooling chamber adaptedto contain an aqueous liquid, a freezing chamber housed within saidcooling chamber 'and sealed with relation thereto, evacuating means, andconnections between said evacuating means and said chambers whereby alow sub-atmospheric,pressure may be produced simultaneously 1n saidchambers by said evacuating means.

3. In an apparatus of the character described, a cooling chamber adaptedto contain an aqueous liquid, a freezing chamber housed within saidcooling element and sealed with respect thereto, evacuating means forsimultaneously producing a sub-atmospheric pressure in said chambers,said freezing chamber having an opening through a wall of the coolingchamber, and a sealing closure for said opening.

4. In an apparatus of the character described, a cooling chamber adaptedto contain an aqueous liquid, a freezing chamber housed within saidcooling chamber and sealed with relation thereto, said freezing chamberbeing surrounded by the liquid in the cooling chamber, evacuating means,and connections between said evacuating means and said chambersrespectively whereby a low sub-atmospheric pressure may be producedsimultaneously in said chambers by said evacuating means, whereby thefreezing chamber is cooled interiorly by the low pressure producedtherein and is cooled externally by the surrounding liquid in thecooling element.

5. In an apparatus of the'character described, a cooling chamber adaptedto contain an aqueous mixture of water and another liquid of a lowerfreezing point than water, a freezing chamber housed within said coolingchamber and sealed with relation thereto, and immersed in said liquidmixture, evacuating means, and connections between said evacuating meansand said chambers whereby a low sub-atmospheric pressure may be producedin said chambers 'by said evacuating means.

6. In an apparatus of the character described, a cooling element adaptedto contain an aqueous liquid, means for evacuating the interior of saidelement to evaporate said liquid to cool the same, a receptacle, saidevacuating means having a discharge opening into said receptacle, an airoutlet from said receptacle, and means between said discharge openingand said air outlet for separating moisture from air before passage fromsaid outlet.

7. In an apparatus of the character described, a cooling element adaptedto contain an aqueous liquid, means for evacuating the interior of said.element to evaporate said,

liquid to cool the same, a housing enclosing said evacuating means, saidevacuating means having a discharge opening into said housing, an airoutlet from the housing, and means between said discharge opening andsaid air outlet for separating moisture from air before passage of theair from said outlet.

8. In an apparatus vof the character de scribed, a cooling elementadapted to contain an aqueous liquid, means for evacuating the interiorof said element to evaporate said liquid to cool the same, a housingenclosing said evacuating means, said evacuating means having adischarge opening into said hous ing, an air outlet from the housing,and means between said discharge opening and said air outlet forseparating moisture from the air before passage of the air from saidoutlet, said last-named means including air passages andmoisture-eliminating means intercepting said passages.

9. In an apparatus of the character described, a cooling element adaptedto contain an aqueous liquid, means for evacuating the interior of saidelement to evaporate said liquid tocool the same, a housing enclosingsaid evacuating means, said evacuating means having a discharge openinginto said housing, an air outlet from the housing, and means betweensaid discharge opening and said air outlet for separating moisture fromthe air before passage from said outlet, said last-named meanscomprising a closure for said housing and including a' perforated plate,and fibrous material overlying the perforations of said plate.

l0. In an apparatus of the character described a cooling element adaptedto contain an aqueous liquid, means for evacuating the interior of saidelement to evaporate said liquid to cool the sa`me,a housing enclosingsaid evacuating means, said evacuating means having a discharge openinginto said housing, an air outlet from the housing, means between saiddischarge and air outlets for separating moisture from the air beforepassage from said outlet, said last-named means comprising a closure forsaid housing and including a perforated plate, fibrous materialoverlying the perforations of said plate, and a cover-plate overlyingsaid fibrous material.

ll. In an apparatus of the character described, a cooling elementadapted to contain an aqueous liquid, means for evacuating the interiorof said element to evaporate said liquid to cool the same, a housingreceptacle enclosing said evacuating means, means for lubricating saidevacuating means, said evacuating means having an exhaust discharge intosaid housing receptacle which constitutes a separator for oil andaqueous liquid, an oil and water separator connected to said housingreceptacle, and means for returning sa-id aqueous liquid rator to saidcooling element.

12. In an apparatus of the character described, a cooling elementadapted to contain an aqueous liquid, means for evacuating the interiorof said element to evaporate said liquid to cool the' same, areceptacle, means for lubricating said evacuating means, said evacuatingmeans having an exhaust discharge into said receptacle which constitutesa separator for o-il and aqueous liquid, an oil and water separatorconnected to said receptacle, and means for returning aqueous liquidfrom said separator to said cooling element, said last-named meansincluding provisions whereby the return of aqueous liquid to saidcooling element is established when the exhausting means is at rest andcut off when the evacuating means operates.

13. An apparatus of the character described, comprising a hollow coolingelement adapted to hold an aqueous liquid, evacuating meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over said liquid and removing vaporof said liquid, lubricating means for the evacuating means, means fromsaid sepafor receiving the exhaust from said evacuating means andseparating aqueous vapor and entrained lubricant from the exhaust, meansto receive condensed aqueous vapor and the lubricant, conduitconnections for feedingcondensed aqueous vapor to the cooling elementand feeding lubricant to the evacuating means respectively, a valvecontrolling each of said conduit connections, and means whereby thevalve in the aqueous liquid conduit opens automatically when theevacuating means is at rest and closes when the evacuating meansoperates, and the valve in the lubricant conduit opens when theevacuating means operates and closes when the evacuating means is atrest. y

14. An apparatus of the character described, comprising a hollow coolingelement adapted to hold an aqueous liquid, evacuating meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over .said liquid and removing vaporof said liquid, 4means for returning tlubricant to said evacuating meansand including a receptacle for receiving lubricant from said evacuatingmeans, and means acting automatically to feed lubricant from saidvreceptacle to said evacuating means when the latter is operating, and tostop said feed when the evacuating means istat rest.

l5. An apparatus of the character described, comprising a hollow coolingelement adapted to hold an aqueous liquid, evacuating meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over said liquid and removing vaporof said liquid, an electric motor for driving said evacuating means,means for furnishing lubricant to said evacuating means and including areceptacle for receiving lubricant from said evacuating means, andhaving a conduit connection with said evacuating means, an electricallyoperated valve in said conduit co-nnection, and a circuit systemincluding said motor and valve whereby the valve is energized to opensaid conduit connection when the motor is running and the valve isdeenergized to close said conduit connection when the motor is at rest.y

16. An apparatus of the character described, comprising a hollow coolingelement adapted to hold an aqueous liquid,evacuat ing meanscommunicating with said element above the liquid level therein forcreating a'subatmospheric pressure over said liquid and removing vaporof said liquid, means for receiving the exhaust from` said`evacuatingmeans and separating from theeXhaust the aqueous vapor and entrainedlubricant, means to receive condensed aqueous vapor and lubricant,conduit connections for returning condensed aqueous vapor to the coolingelement and lubricant to the evacuating means respectively, andautomatic means acting whenthe evacuating means operates to cut oil'feed of the aqueous liquid to the cooling element and establish flow oflubricant to the evacuating means, and acting when the evacuating meansis at rest to establish fiow of aqueous liquid to the cooling element tocut off the flow of lubricant to the evacuating means.

17. An apparatus of the character,` described, comprising a hollowcooling element adapted to hold an aqueous liquid, evacuating meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over saidI liquid and removing vaporof said liquid, means for receiving. the exhaust from said evacuat ingmeans and separatingV from the exhaust the aqueous vapor and entrainedlubricant, means to receive condensed aqueous vapor and lubricant,conduit connections for'returning condensed aqueous vapor to the coolingelement Aand lubricant' to the evacuating means respectively, a valvecontrolling each of said conduit connections, and means Whereby thevalve in the aqueous liquid conduit opens automatically when theevacuating means is at rest' and closes when the evacuating meansoperates, and the valve in the lubricant conduit opens when theevacuating means operates and closes when the evacuating means is atrest.

18. An apparatus of the character described, comprising a hollow coolingelement adapted to hold an aqueous liquid, evacuat-q ing meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over said liquid and removing vaporof said liquid, means for receiving the` exhaust from said evacuat ingmeans and separating from the-exhaust the aqueous vapor and entrainedlubricant,

means to receive condensed aqueous vapor and lubricant, conduitconnectlons for returning condensed aqueous lvapor to the coolingelement and lubricant to the evacuating means respectively, -anelectrically operated valve for controlling each of said conduitconnections and circuit connections for said valves whereby the valve inthe aqueous liquid conduit opens automatically When the evacuating meansis at rest,l and closes when the evacuating means operates, and thevalve in the lubricant conduit opens when 'the evacuating means operatesand closes when the evacuating means is at rest.

19. In a apparatus of the character described, a cooling chambercontaining a liquid comprising a mixture of Water and a liquid having alower freezing point than water, a freezing chamber Within said coolingchamber, and means to produce simultaneously a sub-atmospheric pressurein said chambers.

20. In an apparatus. of the character described, a cooling chambercontaining a liquid comprising a mixture of Water and glycerine, afreezing chamber within said cooling chamber, and means to produce.simultaneously a sub-atmospheric pressure in said chambers.

21. In an apparatus of the character described, a cooling chambercontaining a liquid comprising a mixture of substantially seventy percent. water and thirty per cent. glycerine, a freezing chamber Withinsaid cooling chamber, and means to produce simultaneously asub-atmospheric pressure in said chambers.

22. lAn apparatus of the character described, comprising a hollowcooling element adapted to hold an aqueous liquid, evacuating -meanscommunicating with said element above the liquid level therein forcreating a sub-atmospheric pressure over said liquid .and removing vaporof said liquid, an electric motor for driving said evacuating means,means for furnishing lubricant Y,

to said evacuating means and including a receptacle for receivinglubricant from said evacuating means, and having a conduit connectionwith said evacuating means, and a valve in said conduit connection, saidvalve acting automatically to open said conduit connectionwhen the'motor is running and to close said conduit connection when the motor isat rest.

' In testimony whereof signed our names.

FRANCIS JOSEPH KLEINHANS. HERMAN A. BRANDT.

We have hereunto

